I figured rather than answering every question that gets posted up in different threads I might as well try to answer them all here. Ask them here if these pics don't answer them.
This will be a work in progress:

Makeing your PT Extreme Constant air:

4oz CO2 bottle:
refillable CO2 tank

here are some disposable 4 oz bottles that they sell at most Walmarts made by GameFace. These have about 60+ more shots than a 12 gram co2 cartridge. Some packages come with the needed adaptor.
disposable air tank adaptor looks like this

13cubic inch 3000psi compressed air bottle(HPA) good option for those winter months as vapor CO2 is inferior to HPA.

Vertical adaptor for using hoppers on the pt extreme:
*It bolts right on no modding required*

50 round Hopper:
Reccomended to keep your pistol light but have more ammo